HR: 0830h
AN: OS21C-1132    [PDF]
TI: Ocean Evidence for a Shifting Atlantic Fresh Water Balance Over the Past Four Decades
AU: * Curry, R G
EM: rcurry@whoi.edu
AF: Woods Hole Oceanographic Institution, MS #21, Woods Hole, MA 02543 United States
AU: Dickson, R R
EM: r.r.dickson@cefas.co.uk
AF: CEFAS, Pakefield Rd, Lowestoft, NR33 OHT United Kingdom
AU: Yashayaev, I
EM: YashayaevI@mar.dfo-mpo.gc.ca
AF: Bedford Institute of Oceanography, BIO, Dartmouth, NS B2Y 4A2 Canada
AB: Two long meridional transects through the western and eastern deep basins respectively are used to investigate salinity differences throughout the water columns of the North and South Atlantic Ocean over the past forty years. Toward both poleward limits of these sections we observe freshening over much of the water column, while within the intervening tropics and subtropics, the upper water column in particular has become markedly more saline. Where the dataset permits, it supports the idea that this growing contrast between high and low latitudes is the result of a progressive, if non-steady, evolution throughout the time period examined. For the low latitudes, an evaluation of the amount of annual fresh water loss that could be attributed to evaporation-minus-precipitation (E-P) changes suggests a 5-10% increase in net evaporation rates in recent decades. The radical freshening of the Northern subpolar seas is linked, at least in part, to enhanced efflux of ice and freshwater from the Arctic. In the South Atlantic, freshening is observed in the watermasses that are ventilated in regions where precipitation dominates evaporation. Combined with recent studies in the Mediterranean, Indian and Pacific Oceans, the present investigation extends the evidence that shifts in ocean salinity and fresh water distributions are occurring globally in ways that could reflect an amplification of the hydrologic cycle in recent decades.
DE: 4215 Climate and interannual variability (3309)
DE: 4271 Physical and chemical properties of seawater
DE: 4283 Water masses
DE: 4536 Hydrography
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting